Turbine



- 1,601;6l4 R. w. FLEMING Sept. 28 1926. I

TURBINE Filed Sept. 23

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Sept. 28 1926.

v R. w. FLEMING TURBINE Filed Sept. 23, 1925 5 Sheets-Sheet 4 BY Q OKLATTQRNEY,

INVENTOR. fizelfmz Sept. 28 1926.

R. W. FLEMING TURBINE Filed p 1925 5 Sheets-Sheet s INVENTOR.

$0.567? my 210*? r ATTORNEKF 1,601,614 PATENT OFFICE.

ROBERT WALTON FLEMING, OF THE PLAINS, VIRGINIA.

TURBINE Application filed September 23, 1925. Serial No. 58,201.

This invention relates to steam turbines. Heretofore steam turbineshave, in general, been of two characters. In one case the rotativeeffect has been produced by the inertia of movement of one or more steamjets striking against suitably designed buckets,

such turbines being usually called impulse In the other case alternaterotor and stator elements, each having amultiplioity of blades have beenemployed, the reaction due to expansion and change of direction of flowof the steam producing the r0- tation of the rotor, such turbines beingcommonly known as reaction turbines.

It is well known that, in moving a properly formed aerofoil, such as anairplane wing, through the air a partial vacuum is produced above theaerofoil as well as pressure beneath and the upward tendency due to thispartial vacuum produces what is known as lift. (Practical Aviation byKayward, American Technical Society, Chicago, Illinois, 1919.)

One principal object of this invention is to provide a turbine havingblades and general construction designed to utilize, as fully aspossible, this lift.

This force called lift is generated by placing in a steady fluid flow 'ablade so designe in cross-section and so placed with regard to the flowthat the pressure above the top of the blade is diminished while thatbelow ,the blade is increased. There are then forme two areas ofinfluence. The one above the blade of low-pressure or suction, an thatbelow the blade of thigh-pressure. To secure the best resultsconsecutive and complementary blades must be so shaped and placed thatthese areas do not materially interfere with each other.

A second object of this invention is to increase the efficiency of aturbine by so designing, spacing, and placing the blades with regardto'the steam flow and to one another that, the low-pressure areas abovethe blades be utilized and not interfere with the high areas below theblades or be disturbines.

pressure turbed by the blades themselves. Also that the losses due toeddy-currents, tip clearances, drag, and friction be reduced to aminimum, while at the same time producing the maximum useful workpossible from the steam.

Wherever, in this application, any one of the words steam, air, water,or any other gas or liquid or fluid substance is used it is to be takento mean not only itself but also any one or more of the above namedsubstances used to convert its potential power into work or assistingtherein, by means of blades made fast to a rotor and acted upon by thesubstance.

With the above and other objects in view as will be hereinafterapparent, the invention consists in general of certain novel details ofconstruction and combinations of parts hereinafter fully described,illustrated in the accompanying drawings and specifically claimed.

In the accompanying drawings like characters of reference indicate likeparts in the several views, and:

Figure 1 is a longitudinal median section through a typical turbineconstructed in accordance with this invention.

Figure 2 is an enlarged detail view of a portion of the inlet end ofFigure 1, certain blades being omitted.

Figure 3 is a greatly enlarged perspective of one of the turbine bladesremoved from the rotor.

Figure 1 is an end view of the turbine from the inlet end thereof, thesteam chest having been removed.

Figure 5 is a section on the line 5-5 of Figure 1.

Figure 6 is a Figure 5 the view being detail showing a portion ofenlarged the better (1 to show the blade mounting.

Figure 7 is a diagram showin the crosssectional layout of one of the bades.

Figure 8 is a partially diagrammatic view showing the arrangement of theblades'between the inlet and outlet ends of one stage in a turbineconstructed in accordance herewith, the view being partially broken awayto permit enlargement of the scale used.

Figure 9 is a diagrammatic view showing how the blades may be locatedrelatively to each other and to the steam flow.

In the embodiment of the device here shown a three stage turbine hasbeen illustrated as typical of the invention but it is to be understoodthat the number of stages may be increased or diminished according tothe service to be performed without in any way affecting the principlesof the invention.

Again, as will be seen later, certain angular relations between theentering steam and the blades as well as between the blades themselvesare shown. In like manner these is provided a shaft 10 which is, ofcourse,

supported in suitable bearings one of which is shown at 11. On thisshaft, for each stage of the turbine, there is fixed thereto a hub 12which may carry plates 13, as shown in Figures 1 and 2, or spokes 14, asshown in Figure 5. .On the peripheries of these plates or the outer endsof these spokes, as the case may be, is mounted a frusto-conical rim 15constituting the inner shroud or support for the inner ends of theturbine blades as will.

be presently explained. In the frusto-conical formation of this rim orinner shroud the taper of the frusto-cone is inwardly from the inlet endto the outletend. The rim, hub and connecting members plates or spokesthus constitute a rotor wheel having a frusto-conical periphery taperinginwardly from the inlet end to the outlet end, at such an angle, slopeor curve as will give the best steam expansion with this particulararrangement of blade as herein set forth.

Spaced from the rim 15 is an outer rim or shroud 15 likewise of frustoconical form 7 but tapering in the opposite direction also designed togive the best steam expansion. That is to say the outer shroud tapersout -wardly from the inlet to the outlet end. By

.this means there is provided an annular space between the rimsincreasing in crosssectional area from the inlet to the outletend of theturbine.

An exception is to be noted to this in respect to the first stagewherein the inner and outer shrouds at the inlet end are flaredaway fromeach other to produce the equivalent of a Venturi effect. This is notnecessary however.

At the inlet end of the turbine is provided, a steam chest 18 whichcarries the nozzle supporting flange at the end adjacent the rotor,which consists of inner and outer concentric rings 19 connected bydiagonally disposed partitions 20.. Similarly, between each adjacentpair of stages there are provided nozzle rings each consisting of innerand outer rings 21 connected by diagonal partitions 22. At the outletend of the turbine there is provided the usual exhaust chamber 23. 7

It will beobvious that suitable packing arrangements will be made in theconstruction of the device but it is not thought necessary either toshow or describe anysuch as these details form no part of the presentinvention.

All of the blades 24 are secured to both the inner and the outer shroudby fastenings 25 which may be of any preferred type. In this way thenozzle rings and easing form the stator while the shaft and the partscarried thereby form the rotor.

There will now be considered certain special features of the inventionand first may be mentioned the peculiar cross sectional contour of therotor blades. Each of these blades resembles in cross section the wingof an airplane and as typical of the manner in which such a crosssection may be laid out reference is had to Figure 7. In this figure itwill be seen that is divided into ten equal parts and the greatestcamber 'of the blade is at approximately 30% of this chord from theleading edge a The leading edge along the chord line 02'. being thatpart .of the blade farthest advanced up stream of the fluid flow. Thenose of the blade is rounded and adjacent the leading edge on the underor pressure side of the blade a reverse camber f of small radius ofcurvature is formed just back of such,edge. This reverse camber mergesinto a positive camber which again merges into a relatively long reversecamber h of relatively large radius of curvature near the trailing edge2', the latter being the point where the upper and lower blade surfacesmeet. The upper or lift side of the blade has a continuous camber K.Such a blade closely resembles in cross section the United States Army1919. Of course other be used but all such will and will be genericallydescribed as such, meaning thereby a section wherein lift is developedby partial vacuum on the upper side of the blade and pressure on theunder side of the blade. These vacuum and pressure areas are indicatedat a: and 2/ respectively in Figure 8. The dotted linesindicatingapproximately the boundaries of these areas.

An important feature of the invention is illustratedparticularly inFigures 8 and 9 blade sections may be of aerofoil type the chorddistance ab I standard wing curve No. 5 of and this feature relates tothe peculiar arrangement of the blades so that the steam or otherpropelling fluid acts on these blades in such manner as to produce asubstantially equal pressure on the pressure side of each blade and asubstantially equal lift on In addition, the

shown dotted. Next we angle we increase the line of the bladeinterference of the vacuum area on the top of the blade.

In other words, my blades are so placed around the periphery of therotor wheel that complementary blades will not interfere with oneanother, each succeeding row of blades being also placed along the lineof fluid flow so that the blades will be in the smoothest flow possiblecoming from the preceding row of blades. that no so-called guide bladesare used between the blades in this case and redirec-' tional bladesonly used b the successive stages. As an example 0 the manner in whichthe positions of these blades are determined for this purpose let usassume as shown in Figure 9 that I have a turbine which we desire tohave a blade peripheral linear velocity of 500 foot seconds representedby the length and direction of line dm. This force is in a planeperpendicular to the shaft center line of the turbine, as decide that wewish the total resultant force which acts on the blade to be at an angleof 45 degrees with the planeof rotation of the blades. This resultantforce is represented by line dq making an agle of 45 degrees with dm.This angle gdm may vary in accordance with amount of the component of dqwhich it is desired to have acting along line dm, this component beingdo. By decreasing the do and decrease g0 and vice versa. In thisparticular case however we chose .45'degrees. The resultant force dq ismade up of two forces, one parallel to the chord of the blade andrepresented by sq and called drag, he other perpendicular to the chordof the blade represented by ad and called lift. Sq and 8d are two sidesof a parallelogram of forces and gd is the resultant, angle sdg beingabout 5 degrees in the case of the blade form chosen. Now we know thatthe lift sd is perpendicular to the blade chord (i. e., the blade chordin Figure 7), so we can now lay off line ode at 90 degrees with sd andfor the convenience of construction assume that the forces on the bladeact through the leading edge and thereby lay off the shape marked Bladewith its nose at d and its chord along de.

We have chosen a blade form which gives the best results, or in otherwords, the maximum lift/drag ratio at an angle of attack of plus 10degrees, dl making an angle of lus 10 degrees with cllord edo. It isobserved that this angle of attack of the blade may vary between minus10 degrees and-plus 30 degrees according to the conditions and in orderto prevent the effect called burbling, or in other words, the

formation of 'eddy currents, vortices or the reduction of a bow wave,and at the same time to obtain the maximum lift/drag ratio It will benoted from the preceding will take successive positions attack, thetheoretical determination of therefore we lay olf line' .entrance steam.In this case it will be with the plane of rotation of the blades, or inother words of the rotor wheel.v

In order to place blade de we advance along the rotor wheel making thedistance dd equal the chord length de and lay off chord de parallel tode and locating the leading edge of the blade at d.

In order to lay off blade d 'e" extend chord de indefinitely. Erect edperpendicular to de at 6. Draw rd parallel to dm and so that rd equalsone half chord dc, then draw d"e' so that it will make 5 degrees withline ode, or in other words so that the chord of blade d"e' is rotated 5degrees clockwise from chord of blade de. d is then the nose of the newblade and d 6 equals dc on its chord, which gives the set of the nextrow blades. In like manner the blades may be spaced and each row may beangularly displaced 5 degrees clockwise row. By continuing found thatthe blades as illustrated in Figure 8. As the steam or other fluidleaves the last row of blades, it is directed through another set ofnozzles shown' at 21 in Figure 8 having the same inclination relthisprocess it will be ative to the blades of the second stage of the vrotor as the nozzles at 19 have to the blades of the .first stage.

It is to be understood that this is only one typical example in themanner in which these blades may be layed out and positioned,the-example being givenwith certain assumption including certain bladeperipheral lineal velocity of 500 foot seconds.

is of-course obvious that the same process ma be used with othervelocities as well as.

other nozzle angles anddirections plf t e ro er velocities and anglesbeing attained wit in t e well known manners set forth in the varioustext books on'a'viation and aerodynamics. And it. is not accordinglydeemed necessary to enter further into the theory involved since theaction of known visc'ous fluids on aerofoils-is well known.

.As the fluid enters the inclined nozzles 20 it is 'ven a direction offlow and encounters the rst series of blades atthe left as shown inFigure 8.. Some of the fluid passing above and some beneath. The uppersurfaces of the blades are of larger area than the lower surfaces. Thistogether with its shape will cause a reduced pressure on the upper sideof the blades and an increased pressure below the blades. Thesepressures being diagrammatically illustrated by the dotted curve linesin Figure 8 the position and shape of the blades being such that thesepressure areas interfere as little as possible with each other. Afterthe fluid has passed in succession over all the series of blades in thefirst stage of the rotor its direction is changed by the statornozzles22 and delivered to the second stage rotor and its action'isrepeated and so on through all the turbine stages. I

Having thus described the invention, what is claimed as new, is: I 1. Ina turbine, a rotor, blades attached thereto and arranged in successiverows, the second row taking the fluid from the first row, each bladehaving an aerofoil cross section and set at an angle of attack ofthestream flow such that a partial vacuum Will be formed on its inactivesurface and a pressure on the active surface. -2. In a turbine, a rotor,a plurality of cir cumferential rows of turbine blades, the forward rowset at an angle of attack of the stream flow of between minus 10 30 andthe following row or rows having their cord lines set at an angle to thecord lines of the preceding row. 3. A turbine comprising a rotor in aplurality of stages,'each stage having a plurality of'circumferentialrows of blades having an aerofoil cross section with the leading row ofblades on each stage set at an angle of attack of the stream flow andeach of the succeeding circumferential rows of blades set at an angle ofattack similar to that of the preceding row whereby a smooth stream lineflow from one row of blades to the succeeding row is obtained.

4. A turbine blade having \an aerofoil cross section, and set at anangle of attack of the stream flow of between minus 10 degrees and plus30 degrees, rect a stream of elastic fluid against said blade. v

5. A turbine'blade having a cross sectional contour similar to thestandard Army aeroplane wing designed to produce a partial vacuum on itsinactive surface under the influence of a stream of elastic fluidimpinging upon'its active surface, and means to direct a stream ofelastic fluid against said blade. I

6. A turbine blade having a cross sectional contour similar to thestandard Army aero plane Wing designed to produce a partial vacuum onits inactive surface and a pressure on its active surface under theinfluence of a stream of elastic fluid impinging upon its activesurface, and means to direct and plus and means to diing an aerofoilcross section, the blades of each successive row having their chordlines set at successively greater angles to the chord lines of the firstrow.

9. In a turbine, a rotor including a series of circumferential rows ofblades each having an aerofoil cross section, the blades of each rowhaving their chord lines set at an angle to the chord lines of thepreceding row and offset circumferentially to the blades of saidpreceding row. I

10. In a turbine, a rotor including a series of circumferential rows ofblades each having an aerofoilcross section, and a steam chest having aseries'of angularly disposed nozzles leading therefrom and arrangedtodirect elastic fluid against the first row of said blades.

11. In a turbine, a rotor including a series of rows of blades eachhaving an aerofoil cross section, the blades of each row having theirchord lines set at an angle to the chord lines of the preceding row, anda steam chest having a series of angularly disposed nozzles leadingtherefrom and arranged to direct elastic fluid against the first row ofsaid blades.

p 12. In a turbine, a rotor including a series of rows of blades eachhaving an aerofoil cross section, the blades of each row having theirchord lines set at an angle to the chord lines of-the preceding row andoffset circumferentially. to the blades of said preceding row, and asteanrch having a series of angularly disposed les leading therefrom andarranged to direct elastic fluid against the first row of said blades.

13. In a turbine, a rotor including a-series of rows of blades eachhaving an a'erofoil cross section, the blades of each row havin theirchord lines set at an angle to the chord lines' of the preceding row,the angles at which each row of blades is set with reference to theangles of the preceding row being such as to produce equal effects oneach row ofblades.

14. In a turbine, a rotor including a series of rows of blades eachhaving an aerofoil cross section, the blades of each row having theirchord lines set at an angle to the chord lines of the preceding row, theangles at which each row of blades is set with reference to the anglesof the preceding row being such as to produce a smooth stream line flowfrom one row of blades to the succeeding row.

15. In a turbine, a rotor including a series of rows of blades eachhaving an aerofoil Cal cross section, the blades of each row havingtheir chord lines set at an angle to the chord lines of the precedingrow and offset circumferentially to the blades of said preceding row,the angles at which each row of blades is set with reference to theangles of the preceding row being such as to produce equal effects oneach row of blades.

16. In a turbine, a rotor including a series of rows of blades eachhaving an aerofoil cross section, the blades of each row havin theirchord lines set at an angle to the chor lines of the preceding row andoffset circumferentialy to the blades of said preceding row, to cause asmooth stream line flow from one row of blades tov the succeedingrow.

17. In a turbine, a rotor including a series of rows of blades spacedcircumferentially of the turbine and each having an aerofoil crosssection arranged to produce a vacuum area on the inactive side of theblade and a pressure area on the active side of the blade, thecircumferential spacing of the blades in each row being such as'toprevent material interference between the vacuum and pressure areas, allblades of each stage of the turbine being mounted on a common shroud.18. In a turbine, a rotor including a series of rows of blades spacedcircumferentially of the turbine and each having anaerfoil cross sectionarranged to area on-the inactive surface of the blade and a pressurearea on the active surface of the blade, the circumferential spacing ofthe blades in each row being such as to prevent material interferencebetween thevacuum and pressure areas, the blades of each row havingtheir chord lines set at an angle to the chord lines of the precedingrow.

19. In a'turbine, a rotor including a series of rows of blades spacedcircuinferentially 'of the turbine and eachlhaving an aerofoil crosssection arranged to produce a vacuum area on the inactive side of theblade and a pressure area on the active side of the blade, thecircumferential spacing of the blades in each row being such as toprevent material interference between the vacuum and pressure areas, theblades of each row having their chord lines set at an angle to the chordlines of the preceding row and oil'- set circumferentially to the bladesof said preceding row. i

20. In a turbine, a. rotor including a. series of rows of blades spacedcircumferentially produce a vacuum of the turbine and each having anaerofoil cross section arranged to produce a vacuum area on the inactiveside of the blade and a pressure area on the active side of the blade,the circumferential spacing of the blades in each row being such as toprevent material interference between the vacuum and pressure areas, anda steam chest having a series of angularly disposed nozzles leadingtherefrom and arranged to direct elastic .fluid against the first row ofsaidblades.

21. In a turbine, a rotor including a series of rows of blades spacedcircumferentially of the turbine and each having an aerofoil crosssection arranged to produce a vacuum area on the inactive side of theblade and a pressure area on the active side of the blade, thecircumferential spacing of the blades in each row being such as toprevent material interference between the vacuum and pressure areas, theblades of each row having their-chord lines set at an angle to the chordlines of the preceding row, and a steam chesthaving a series ofangularly disposed nozzles leading therefrom and arranged to directelastic fluid against the first row of said blades.

22. In a turbine, a rotor including a series of rows of blades spacedcircumferentially of the turbine and each having an aerofoil crosssection arranged to produce a vacuum area on the inactive side oftheblade and a pressurearea on the active side of the blade, thecircumferential spacing of the blades in each row being such as toprevent material interference between the vacuum and pressure areas, theblades of each row having their chord lines set at an angle to the chordlines of the preceding row, the angles at which each row of blades isset with reference to the angles of the preceding row being such as toproduce equal effects on each row of blades. a

1 23. In a turbine, a rotor including a series of rows of bladesspacedcircumferentially of the turbine and each cross section arrangedto produce a vacuum area on the inactive side of the blade and apressure area on the active side of the blade, the circumferentialspacing of the blades in each row being such as to prevent materialinterference between the vacuum and pressure areas a smooth stream lineflow from one row of blades to the succeeding row.

In testimony whereof he aifixes his signature.

having an aerofoil

